Pyrolytic oven

ABSTRACT

The normal door sealing gasket of the oven is incomplete to form an ambient air inlet of predetermined width at the bottom central region of the interface of the closed door and the oven liner. At this region, there is an opposed baffle of greater length beneath the inlet and engaged by the inner door liner to form therewith lateral ambient air passage means for flow therethrough of such air to the inlet and hence the interior of the oven. Such passage means prevents flame from being expelled from the oven in its pyrolytic or high temperature cleaning cycle of operation.

0 United States Patent 1191 1111 3,7393% Gilliom June 12, 1973 PYROLYTIC OVEN 3,561,423 2 1971 Holtkamp 126/198 [75] Inventor: John W. Gilliom, Mansfield, Ohio FOREIGN PATENTS OR APPLICATIONS 73 Assignee: The pp p y Mansfield, 533,223 2/1941 Great Britain.. 219/400 Ohio Primary Examiner-Volodymyr Y. Mayewsky Flled: July 1972 Att0rneyEdwin E. Donnelly, Jr. [21] Appl. No.: 273,593

[57] ABSTRACT [52] U S Cl 219/393 126/21 R 219/400 The normal door sealing gasket of the oven is incom- [51] F27d 11/02 plete to form an ambient air inlet of predetermined [58] Fie'ld 393 399 width at the bottom central region of the interface of R 21 A the closed door and the oven liner. At this region, there is an opposed baffle of greater length beneath the inlet [56] References Cited and engaged by the inner door liner to form therewith lateral ambient air passage means for flow there- UNITED STATES PATENTS through of such air to the inlet and hence the interior 2,922,018 H1960 Walkoe 219/393 of th oven Such assage means prevents flame from 310591089 10/1962 swlsiher being expelled from the oven in its pyrolytic or high 3:135:52 temperature cleaning cycle of operation. 3,450,126 6/1969 Vonderhaar 126/200 4 Claims, 3 Drawing Figures 1 PYROLYTIC OVEN This invention relates to the pyrolytic type of selfcleaning oven in which there is provided a cleaning cycle during which the oven is heated to a temperature within the range of from about 750F to about 950F for decomposing food soil on the interior surfaces and, more particularly, to improved means for the admittance of ambient air to the oven in such a cleaning operation.

As disclosed in US. Pat. No. 3,348,023, such a selfcleaning action conventionally employs an oxidation unit or catalytic device in the usual venting of the oven primarily for eliminating smoke from the exhaust, and the operation in this respect is aided by a predetermined inflow of room air to the oven cavity. The patent suggests that one way of supplying additional oxygen by such room air would be to provide a gap between the oven door and the cavity it closes, but indicates that this is not a satisfactory answer and, instead, provides air inlet means through the body of the door itself and preferably including a plurality of fine mesh metal screens. The problem is, briefly, to protect against flame in or at the exterior of the air inlet means when high soiling conditions exist and combustion thereof accordingly a greater problem.

The noted solution provided by the patent, while effective, requires the door to have a specially constructed air passage therein and, in actual practice, the same has been equipped with the flame arresting screen assembly in such interior door passage.

It has been found that the problem can be much more easily and economically solved by the present invention.

In particular contrast, and as its primary object, the present invention does not require special design and tooling of the oven door in the manner noted in the patent and does in fact utilize an air inlet at the interface of the door and the oven body, with a relatively simple and inexpensive modification of the two effectively fulfilling the objective of admitting room air without the danger of flame occurrence under even very heavy soil conditions in the high temperature pyrolytic cleaning operation.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail a certain illustrative embodiment of the invention, this being indicative, however, of but one of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a perspective view of one form of conventional range having upper and lower ovens, with the latter of the pyrolytic type as above discussed, the door of such lower oven being removable and detached more readily to illustrate the present invention;

FIG. 2 is a front fragmented view of the lower oven construction with the door in closed condition and the exterior broken away in the area of the lower edge of the door where the ambient air inlet means is provided in accordance with the invention; and

FIG. 3 is a fragmented transverse section of the FIG. 2 assembly as viewed from the plane of the line 3-3 therein.

Referring to the drawing in detail, the range designated generally by reference numeral is of generally known configuration having a high or eye-level oven 11 spaced appreciably above a cooking top 12 in which surface elements 13 are provided, and a lower oven 14 the operation of which includes a pyrolytic or high temperature cleaning cycle. Such lower oven has a removable oven door 15 to be described more in detail later normally supported detachably on hinge means 16 for swinging movement generally about its lower edge.

Such pyrolytic oven 14 is shown as having upper and lower electric heating elements 17 and 18, respectively, a suitable form of interlocked door latch, the handle of which shows at 19 to preclude opening of the door while the oven is at a temperature within the cleaning range; the oven will also be equipped with an exhaust at the rear, not shown, in which there is a suitable oxidation unit to eliminate smoke, with all of these details of construction well-known and also to a significant extent shown in the above-mentioned US. Pat. No. 3,348,023.

With continued reference to the lower pyrolytic oven, it includes an inner liner 20 having a front flange 21 (FIG. 3) and there is a front cabinet wall 22 relatively projecting therebeneath. The space beneath this oven is in the illustrated embodiment provided with a storage drawer 23.

The oven door 15 itself includes an outer liner 24 and an interfitting inner liner 25 together forming a compartment filled with suitable thermal insulating material 26. The inner liner has a rectangular inwardly offset portion 27 dimensioned so that it is, in the closed door condition, opposed at its periphery to the front 21 of the oven liner, and the former carries a woven glass gasket 28 held thereagainst by a gasket retainer 29. The latter is here in the form of a dished metal sheet having a flange 30 about its edge which engages firmly against the gasket, with the retainer secured to the inner door liner 27 by an affixed inner channel 31 and bolts 32.

This door gasketing is, however, unconventional in that there is a discontinuity therein at the central bottom portion of the inside of the door, which means of course that an air gap 33 is provided over the extent of this discontinuity or interruption of the gasket sealing of the door and the oven liner at such location. Ambient or room air can thus be drawn into the oven through the thus formed inlet, the width W-l of which is roughly from one-fourth to one-third of the interior width of the oven liner.

A baffle strip 34 is secured to the range cabinet wall 22 below the oven, for example, by screws 35 and has a curved forwardly and downwardly projecting lip 36 which is resiliently engaged by the rounded outermost edge of the inner door liner 25 when the door is closed, as shown clearly in FIG. 3. This baffle, also centered with respect to the access opening or front of the oven, is of a length W-2 which is slightly more than twice the width of the air gap W-l. As a more specific example, the latter can be on the order of 6 inches and the former 14 inches in an oven liner application in which the width thereof is close to 20 inches or within the range of from about 19 to 23 inches. Cooperatively, they clearly form an admittance passage through which the room air must pass laterally from the sides over the baffle lip to reach the inlet 33 to the oven interior, as shown by the arrows, and it has been found that the cooling effect which thus obtains is adequate to prevent flame from being expelled from the oven in the high temperature cleaning operation.

It will also be appreciated that the foregoing is not only contrary to teaching of the referenced prior art patent, but, by comparison, is an extremely simple alternative. The discontinuity of the normal door sealing gasket to provide the gap at the interface of the door and the oven presents no real assembly problem and, at the same time, eliminates the need to form special passages and provide components within the interior of the door itself as taught by the patent. Obviously, the baffle is an inexpensive element and one that can very readily be applied in manufacture of the oven.

The invention, moreover, can be used as well with different types of ovens, for example, with built-in ovens or any other type of known pyrolytic oven where such an ingress of room air is needed or desired to enhance the self-cleaning operation in particular.

I, therefore, particularly point out and distinctly claim as my invention:

1. A high temperature oven comprising walls forming an oven liner having an access opening at the front about which there is a flange portion, heating means within the liner for raising the temperature therein, a door for closing said access opening having an inwardly projecting part uniformly to confront the liner flange portion, discontinuous elongated gasket means carried by one of said flange portions and door part to seal the same about the top, sides and predetermined side bottom portions of the access opening, the discontinuity of the gasket means thus providing a space between the ends of the gasket means defining an air inlet for the oven liner at its bottom central region, and an elongated baffle secured to the enclosure means just beneath the air inlet means and having a forwardly projecting portion which is engaged by the closed door outwardly of the gasket means, thereby to define passage means through which air can flow over the baffle means at the door and oven interface to the air inlet means for admittance to the liner.

2. An oven as set forth in claim 1, wherein the bottom air inlet means is from about one-fourth to about onethird of the interior width of the oven.

3. An oven as set forth in claim 2, wherein the extent of the baffle means is slightly more than twice the width of the air inlet means.

4. An oven as set forth in claim 1, wherein the heating means is electrical resistance heating means. 

1. A high temperature oven comprising walls forming an oven liner having an access opening at the front about which there is a flange portion, heating means within the liner for raising the temperature therein, a door for closing said access opening having an inwardly projecting part uniformly to confront the liner flange portion, discontinuous elongated gasket means carried by one of said flange portions and door part to seal the same about the top, sides and predetermined side bottom portions of the access opening, the discontinuity of the gasket means thus providing a space between the ends of the gasket means defining an air inlet for the oven liner at its bottom central region, and an elongated baffle secured to the enclosure means just beneath the air inlet means and having a forwardly projecting portion which is engaged by the closed door outwardly of the gasket means, thereby to define passage means through which air can flow over the baffle means at the door and oven interface to the air inlet means for admittance to the liner.
 2. An oven as set forth in claim 1, wherein the bottom air inlet means is from about one-fourth to about one-third of the interior width of the oven.
 3. An oven as set forth in claim 2, wherein the extent of the baffle means is slightly more than twice the width of the air inlet means.
 4. An oven as set forth in claim 1, wherein the heating means is electrical resistance heating means. 